Search for:
Base failures that cause violations of safety goals of at least two different system elements.
Explanation:
Base failures will be searched for that are linked to two or more different violations of safety goals. Such violations of safety goals must be simultaneously anchored at least at two different system elements. It is irrelevant for the search whether the violations of safety goals are reached via single-point fault paths or multiple-point fault paths.
Example:
Abbreviations:
- The sample structure above consists of four system elements. Two system elements TE1 and TE2 are assigned to
the root element, which have altogether three different safety goals
each with one violation of safety goal 
.
The last system element BSE
has three base failures including functions.
- The following failure graph shows how the base failures BF are linked to the violations of safety goals.
- Two placeholders for the failure type are automatically assigned in the IQ Software to a violation of safety goal. This is represented in the failure graph and the failure net. If you anchor a violation of safety goal in the failure graph or the failure net these placeholders for failure types are automatically shown next to the violation of safety goal in the direction of causes. The failure types tell if the failures leading to a violation of safety goal according to ISO 26262 are single-point faults or multiple-point faults.
- The considered Quality Rule (QR) detects base failures (BF), which are linked to two or more different violations of safety goals and where these violations of safety goals must be simultaneously anchored at least at two different system elements. It is irrelevant for the search whether the violations of safety goal are reached via single-point fault paths or multiple-point fault paths.
Search result:
Even though each of the three existing BFs leads to two different violations of safety goals, only two of them match the filter criteria of the Quality Rule, i.e., that these violations of safety goals must be simultaneously anchored at least at two different system elements.
Therefore, only the base failures BF2 and BF3 are marked as hits.